1. Field of the Invention
The present invention relates to a device for vertically moving a slider along a vertical support, fixing the slider at any desired position and releasing the slider from the support, more particularly, concerns with an improvement in a vertical movement and fixture device comprising a groove disposed inside the support, a block base slidably fit in the groove, a slider fixed to the block base and a means for fixing and releasing the block base at any desired position.
2. Prior Art
In the case of the dental tomograph P for photographing entire jaw shown in FIG. 5, for example, it is essential to vertically move and fix a slider 2 comprising the above-mentioned groove, block base, slider and means for fixing and releasing the block base at any desired position on a vertical support 1. In this case, the slider 2 includes an X-ray photographing arm A comprising an X-ray generator X and an X-ray film F secured to both ends of the arm, a carriage C for hanging the arm, a patient's head holding member H, other mechanical elements, electrical circuits and the like. Therefore, a block base 3 (not shown in FIG. 5) must be firmly fixed to the walls of the groove 11 of the support 1. In addition, since the slider needs to be released frequently during use, the release operation must be easy.
A conventional means for fixing and releasing the slider uses an electromagnetic brake between the slider and the support. This type can deliver great fixing force and promptly release the force. However, since this type needs electrical circuits, the cost is high. This is a great disadvantage. A screw tightening method is also used to fix the slider on the support. In the case of this entirely mechanical type, the slider cannot be fixed or released by simple operation. Furthermore, it is difficult to obtain constant and great fixing force, since the fixing force of this type is dependent on the tightening force of the screw.